What type of ultrapure water should I use for HPLC (UHPLC) analysis?

As “HPLC-grade water” gradually becomes a household word throughout the scientific industry, the importance of ultrapure water in HPLC and UHPLC analysis is no longer a new topic. Achieving reliable and reproducible results is an eternal pursuit for all scientists, so RephiLe is willing to spare no effort to emphasize how to select a proper water purification system that can provide you with the right volume and quality of HPLC-grade water for your applications.

As a reliable and established tool in the analytical industry, HPLC or UHPLC (an extension of HPLC, which can operate at pressures up to 15,000 psi and take advantage of sub-2 μm particle sizes) is widely used in food analysis, environmental analysis, biochemical research as well as in-process quality control testing in the pharmaceutical industries. With appropriate chromatographic detectors and running conditions, compounds in trace concentrations as low as parts per trillion (ppt) level can easily be identified by the system. Water is one of the most commonly used solvents in these analyses. Any unknown material introduced by the water can add variables to the analysis work. These unknown materials include particles, ions, organic substances, dissolved atmospheric gases, bacteria or microorganisms.

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Unknown materials in tap water

Water with particle impurities can block chromatography columns and reduce measurement performance by affecting the selectivity of the stationary phase, affecting peak resolution, integration, and analysis baselines. Ionic contaminants can aggregate with specific analytes. This will produce adduct peaks that interfere with mass spectrometry measurements. In order to get stable retention time and constant peak responses, it is required to use the fresh-made HPLC grade water during the (U)HPLC analyses, which is ultra-pure water (conductivity-  16-18 MΩ·cm) with low UV absorbance, right after being produced by an ultrapure water system. A 0.22 µm filter is often used at the point of dispensing as a final polishing step to guarantee the best result. A good starting point for describing HPLC-grade water is to look at the specification for ASTM Type 1 Reagent grade water.

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ASTM Type I Reagent grade water

Besides those basic conditions, HPLC-grade ultrapure water purification system should contain a combination of reverse osmosis, ion-exchange, filtration and ultrafiltration, ultraviolet irradiation, and other methods according to the Japanese Standard Association Group. The amount of total organic compound (TOC) is one of the most crucial factors. To monitor accurately the level of organics in water, an online TOC monitor downstream of the system is strongly recommended.   Let us take a closer look at the schematic flow diagram by using the Genie G water purification system as an example for a better understanding.

Genie G ultrapure water purification system flow chart
  • AC Pack: Remove dissolved gasses, organics and dissolved chlorine.
  • P Pack: Act as pre-filtration, P Pack removes dissolved solids.
  • RO Pack(s): Using the technology of reverse osmosis, it removes dissolved salts and ions.
  • EDI module: Electrodeionization has a great ability to remove ions constantly so it can maintain the value of the conductivity of the water maintain consistently.
  • UV Lamp(s): Remove organic traces to the specific level to keep noise level at a minimum.
  • T Pack: Maintain continuous recirculation of the water in tank
  • Built-in pump system: To reach constant water flow rate with controlled pressure
  • Conductivity/Resistivity sensor inlet/outlet: To monitor and display the quality data of water

With the advanced purification technologies and an optimized purification sequence, Genie G water purification system can consistently and reliably provide standard HPLC-grade water that exactly meet your needs. Other than that, this smart system is easy-to-use, aiming to bring you improved productivity and maximum flexibility in using your lab space. Definitely, Genie G will help you perform HPLC and UHPLC analyses more efficiently and accurately.

About RephiLe:

Driven by innovation and quality, RephiLe is a dedicated provider of water purification systems and laboratory filtration products. At the same time, RephiLe produces comprehensive consumables that can be used in Millipore lab water systems with reliable performance. It is RephiLe’s commitment to becoming a partner of choice for customers in the area of life science and biotechnology. The company is striving to bring superior quality, high value and innovative purification tools to enable and accelerate the advancement of the life sciences and technologies. Products are being sold to over 90 countries worldwide.